Analog continuous time matched pulse shaping transmitter and receiver filters

Abstract

The present invention provides a transmission system, including: a transmitter including a transmitter filter; a receiver including a receiver filter; and a communicative coupling between the transmitter and the receiver; wherein the transmitter filter and the receiver filter are matched for noise reduction, and wherein the combined responses of the transmitter filter and the receiver filter satisfy the Nyquist criteria. Optionally, the transmitter filter includes a pulse shaping quasi digital finite impulse response filter. Optionally, the receiver filter includes an inductor-capacitor ladder based filter.

What is claimed is: 
     
       1. A circuit, comprising:
 a transmitter filter comprising a quasi digital filter that utilizes digital data as inputs provided to a shift register buffer stage and clocked through the shift register buffer stage in a discrete-time manner and outputs of the shift register buffer stage that are continuous-time analog signals which are weighted and summed in an analog domain; 
 a receiver filter comprising an analog filter; and 
 a communicative coupling between the transmitter filter and the receiver filter; 
 wherein the transmitter filter and the receiver filter are matched for noise reduction, wherein the transmitter filter compensates for non-ideal filtering properties of the receiver filter by adjusting its taps, and wherein the combined responses of the transmitter filter and the receiver filter satisfy the Nyquist criteria; 
 wherein the transmitter filter comprises a pulse shaping quasi digital finite impulse response filter, wherein the transmitter filter is dynamically adaptable to compensate for optical channel distortion impairments; and 
 wherein the receiver filter comprises an inductor-capacitor ladder based filter, wherein only a single separate receiver filter is used per I and Q data streams prior to demodulation and decision slicing of a multi-level, multi-bit modulation formatted signal. 
 
     
     
       2. The circuit of  claim 1 , wherein the pulse shaping quasi digital finite impulse response filter utilizes a combination of digital delays and analog coefficient control and tap summation. 
     
     
       3. The circuit of  claim 1 , wherein the pulse shaping quasi digital finite impulse response filter is calibrated to compensate for residual manufacturing imperfections of both transmitter and receiver components. 
     
     
       4. The circuit of  claim 1 , wherein the pulse shaping quasi digital finite impulse response filter and transmitter data processing are utilized to provide simultaneous pulse shaping and digital-to-analog conversion required for multi level, multi bit modulation formats. 
     
     
       5. The circuit of  claim 1 , wherein the inductor-capacitor ladder based filter is implemented in one of CMOS and BiCMOS circuitry. 
     
     
       6. The circuit of  claim 1 , wherein the transmitter filter and the receiver filter are selected and matched such that they provide optimized suppression of one or more of inter signal interference and inter channel interference. 
     
     
       7. A transmission system, comprising:
 a transmitter comprising a transmitter filter comprising a quasi digital filter that utilizes digital data as inputs provided to a shift register buffer stage and clocked through the shift register buffer stage in a discrete-time manner and outputs of the shift register buffer stage that are continuous-time analog signals which are weighted and summed in an analog domain; 
 a receiver comprising a receiver filter comprising an analog filter; and 
 a communicative coupling between the transmitter and the receiver; 
 wherein the transmitter filter and the receiver filter are matched for noise reduction, wherein the transmitter filter compensates for non-ideal filtering properties of the receiver filter by adjusting its taps, and wherein the combined responses of the transmitter filter and the receiver filter satisfy the Nyquist criteria; 
 wherein the transmitter filter comprises a pulse shaping quasi digital finite impulse response filter, wherein the transmitter filter is dynamically adaptable to compensate for optical channel distortion impairments; and 
 wherein the receiver filter comprises an inductor-capacitor ladder based filter, wherein only a single separate receiver filter is used per I and Q data streams prior to demodulation and decision slicing of a multi-level, multi-bit modulation formatted signal. 
 
     
     
       8. The transmission system of  claim 7 , wherein the pulse shaping quasi digital finite impulse response filter utilizes a combination of digital delays and analog coefficient control and tap summation. 
     
     
       9. The transmission system of  claim 7 , wherein the pulse shaping quasi digital finite impulse response filter is calibrated to compensate for residual manufacturing imperfections of both the transmitter and the receiver. 
     
     
       10. The transmission system of  claim 7 , wherein the pulse shaping quasi digital finite impulse response filter and transmitter data processing are utilized to provide simultaneous pulse shaping and digital-to-analog conversion required for multi level, multi bit modulation formats. 
     
     
       11. The transmission system of  claim 7 , wherein the inductor-capacitor ladder based filter is implemented in one of CMOS and BiCMOS circuitry. 
     
     
       12. The transmission system of  claim 7 , wherein the transmitter filter and the receiver filter are selected and matched such that they provide optimized suppression of one or more of inter symbol interference and inter channel interference. 
     
     
       13. A transmission method, comprising:
 at a transmitter, filtering a signal utilizing a transmitter filter comprising a quasi digital filter that utilizes digital data as inputs provided to a shift register buffer stage and clocked through the shift register buffer stage in a discrete-time manner and outputs of the shift register buffer stage that are continuous-time analog signals which are weighted and summed in an analog domain; 
 transmitting the signal from the transmitter to the receiver utilizing a communicative coupling; and 
 at a receiver, filtering the signal utilizing a receiver filter comprising an analog filter; 
 wherein the transmitter filter and the receiver filter are matched for noise reduction, wherein the transmitter filter compensates for non-ideal filtering properties of the receiver filter by adjusting its taps, and wherein the combined responses of the transmitter filter and the receiver filter satisfy the Nyquist criteria; 
 wherein the transmitter filter comprises a pulse shaping quasi digital finite impulse response filter, wherein the transmitter filter is dynamically adaptable to compensate for optical channel distortion impairments; and 
 wherein the receiver filter comprises an inductor-capacitor ladder based filter, wherein only a single separate receiver filter is used per I and Q data streams prior to demodulation and decision slicing of a multi-level, multi-bit modulation formatted signal. 
 
     
     
       14. The transmission method of  claim 13 , wherein the transmitter filter and the receiver filter are selected and matched such that they provide optimized suppression of one or more of inter signal interference and inter channel interference.